DCL-02-089, CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes

CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes

ML022170148
Person / Time
Site:	Diablo Canyon
Issue date:	07/26/2002
From:	Oatley D Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
50-275-OL, 50-323-OL, DCL-02-089
Download: ML022170148 (7)

Text

PacificGas and Electric Company David H.Oatley Diablo Canyon Power Plant Vice President PO Box 56 Diablo Canyon Operations Avila Beach, CA 93424 805.5454350 July 26, 2002 Fax: 805.545.4234 PG&E Letter DCL-02-089 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes

Dear Commissioners and Staff:

Pursuant to 10 CFR 50.46, this letter provides an annual report of changes in the Westinghouse emergency core cooling system evaluation models that affect peak cladding temperature (PCT) calculations for Diablo Canyon Power Plant, Units I and 2. There have been no changes or errors identified in the PCT calculations associated with the best estimate large-break loss of coolant accident (LOCA) evaluation models since the last annual report submitted via PG&E Letter DCL-01 -078, dated July 26, 2001. The summary of the current PCT margin allocations is provided in the enclosure. The PCT values are as follows:

Small-Break LOCA Best Estimate Large-Break LOCA Reflood 1 Reflood 2 Unit I (no change): 1317 OF 2013 OF 1980 OF Unit 2 (no change): 1306 OF 2013 OF 1980 OF The PCT values remain within the 2200°F limit specified in 10 CFR 50.46. As indicated in PG&E Letter DCL-00-1 34, dated October 19, 2000, PG&E proposes to perform a reanalysis for large-break LOCA by July 26, 2003.

A A member of the STARS (Strategic Teaming and Resource Sharing) ALliance Catlaway a Comanche Peak 9 Diablo Canyon @ Palo Verde

• South Texas Project a Wolf Creek

Document Control Desk PG&E Letter DCL-02-089 July 26, 2002 Page 2 Sincerely, David H. Oatley mrb Enclosure cclenc: Ellis W. Merschoff David L. Proulx Girja S. Shulka Diablo Distribution A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Caltaway

• Comanche Peak e Diablo Canyon e Palo Verde

• South Texas Project

• Wolf Creek

ENCLOSURE PG&E Letter DCL-02-089 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM EVALUATION MODEL CHANGES THAT AFFECT PEAK CLADDING TEMPERATURE Pursuant to 10 CFR 50.46, this enclosure provides an annual report of changes in the Westinghouse emergency core cooling system (ECCS) evaluation models that affect peak cladding temperature (PCT) calculations for Diablo Canyon Power Plant (DCPP), Units 1 and 2. This report is based on changes described in the following Westinghouse 10 CFR 50.46 notification letter:

Westinghouse Letter PGE-02-4, dated March 1, 2002, "Diablo Canyon Units 1 and 2, 10 CFR 50.46 Annual Notification and Reporting for 2001."

Attachment A to this enclosure provides DCPP Unit 1 small-break (SB) LOCA and best estimate large-break (LB) LOCA PCT Margin Utilization Sheets.

Attachment B to this enclosure provides DCPP Unit 2 SBLOCA and best estimate LBLOCA PCT Margin Utilization Sheets. There have been no changes to the ECCS evaluation models for either Unit 1 or 2 since the last PG&E report DCL-01-078 dated July 26, 2001. The summary of the current PCT margin allocations are provided in Attachments A and B.

As indicated in PG&E Letter DCL 00-134, dated October 19, 2000, PG&E proposes to perform reanalysis for LBLOCA by July 26, 2003.

The PCT values that are calculated in Attachments A and B are listed below.

SBLOCA Best Estimate LBLOCA Reflood 1 Reflood 2 Unit 1 (no change): 1317 IF 2013 OF 1980 OF Unit 2 (no change): 1306 OF 2013 OF 1980 OF

ATTACHMENT A PG&E Letter DCL-02-089 DCPP UNIT I PEAK CLADDING TEMPERATURE MARGIN UTILIZATION SMALL-BREAK LOCA PG&E Letter1 A. ANALYSIS OF RECORD PCT = 1304°F DCL-99-096 B. PERMANENT 10 CFR 50.46 2 ECCS MODEL ASSESSMENTS

1. NOTRUMP Mixture Level APCT= 13 0F DCL-00-107 Tracking/Region Depletion Errors C. 10 CFR 50.59 AND 10 CFR 50.92 SAFETY EVALUATIONS

1. None APCT = 0OF D. OTHER MARGIN ALLOCATIONS

1. None APCT = 0oF LICENSING BASIS PCT + MARGIN ALLOCATION PCT = 1317°F For those issues that have been previously reported under 10 CFR 50.46, a PG&E letter number is listed.

2 Only permanent assessments of PCT margin are included. Temporary PCT allocations that address current LOCA model issues are not considered with respect to 10 CFR 50.46 reporting requirements.

ATTACHMENT A PG&E Letter DCL-02-089 DCPP UNIT 1 PEAK CLADDING TEMPERATURE MARGIN UTILIZATION BEST ESTIMATE LARGE-BREAK LOCA PG&E Letter1 Reflood Reflood 1 2 A. ANALYSIS OF RECORD 1976 0 F 1964 0 F DCL-00-107 APCT APCT B. PERMANENT 10 CFR 50.46 2 ECCS MODEL ASSESSMENTS

1. Intercell Force Gap Numbering DCL-00-107 33 0 F 67 0 F Error

2. Vessel Channel DX Error (1998) 0oF -67 0 F DCL-00-107

3. MONTECF Decay Heat 40 F 160 F DCL-01-078 Uncertainty Error C. 10 CFR 50.59 AND 10 CFR 50.92 SAFETY EVALUATIONS D. OTHER MARGIN ALLOCATIONS

1. None 0OF 0OF LICENSING BASIS PCT + MARGIN 2013°F 1980°F ALLOCATION PCT

ATTACHMENT B PG&E Letter DCL-02-089 DCPP UNIT 2 PEAK CLADDING TEMPERATURE MARGIN UTILIZATION SMALL-BREAK LOCA PG&E Letter1 A. ANALYSIS OF RECORD PCT = 1293 0 F DCL-99-096 B. PERMANENT 10 CFR 50.46 2 ECCS MODEL ASSESSMENTS

1. NOTRUMP Mixture Level APCT = 13 'F DCL-00-107 Tracking/Region Depletion Errors C. 10 CFR 50.59 AND 10 CFR 50.92 SAFETY EVALUATIONS

1. None APCT = 0 'F D. OTHER MARGIN ALLOCATIONS

1. None APCT = 0 'F LICENSING BASIS PCT + MARGIN ALLOCATION PCT = 1306°F For those issues that have been previously reported under 10 CFR 50.46, a PG&E letter number is listed.

2 Only permanent assessments of PCT margin are included. Temporary PCT allocations that address current LOCA model issues are not considered with respect to 10 CFR 50.46 reporting requirements.

ATTACHMENT B PG&E Letter DCL-02-089 DCPP UNIT 2 PEAK CLADDING TEMPERATURE MARGIN UTILIZATION BEST ESTIMATE LARGE-BREAK LOCA PG&E Letter1 Reflood Reflood 1 2 A. ANALYSIS OF RECORD 1976 0 F 1964oF DCL-00-1 07 APCT APCT B. PERMANENT 10 CFR 50.46 2 ECCS MODEL ASSESSMENTS

1. Intercell Force Gap Numbering 330F 67 0 F DCL-00-107 Error

2. Vessel Channel DX Error (1998) 0oF -67 0 F DCL-00-1 07

3. MONTECF Decay Heat 40 F 160 F DCL-01-078 Uncertainty Error C. 10 CFR 50.59 AND 10 CFR 50.92 SAFETY EVALUATIONS D. OTHER MARGIN ALLOCATIONS

1. None 0OF 0oF LICENSING BASIS PCT + MARGIN 2013°F 1980°F ALLOCATION PCT